Energy release using tunable reactive materials

Abstract

A reactive material stack with tunable ignition temperatures is provided by inserting a barrier layer between layers of reactive materials. The barrier layer prevents the interdiffusion of the reactive materials, thus a reaction between reactive materials only occurs at an elevated ignition temperature when a certain energy threshold is reached.

What is claimed is: 
     
       1. A method of forming a reactive material stack, the method comprising:
 forming a layer of a first reactive material over a substrate; 
 forming a barrier layer over the layer of the first reactive material; 
 forming a layer of a second reactive material over the barrier layer; 
 forming another barrier layer over the layer of the second reactive material; and 
 repeating the forming of the layer of the first reactive material, the forming of the barrier layer, the forming of the second reactive material, and the forming of the another barrier layer to provide a desired thickness for the reactive material stack, wherein each of the barrier layer and the another barrier layer comprises a stack of, and from bottom to top, Al x O y /Ta/Ta x O y  or, Al x O y /Ta/Ta x O y /Ta/Ta x O y , wherein x is from 1 to 3 and y is from 1 to 5. 
 
     
     
       2. The method of  claim 1 , wherein the desired thickness is from 0.5 μm to 10 μm. 
     
     
       3. The method of  claim 1 , wherein the first reactive material and the second reactive material are selected from the group consisting of Ni/Al, Al/Pd, Cu/Pd, Nb/Si and Ti/Al. 
     
     
       4. The method of  claim 1 , further comprising reacting the first reactive material and the second reactive material, wherein the reaction causes intermixing of the first reactive material and the second reactive material to form an alloy, intermetallic or a composite of the first reactive material and the second reactive material. 
     
     
       5. The method of  claim 4 , wherein the reaction comprises an ignition caused by one of mechanical stress, an electrical spark, or a laser pulse. 
     
     
       6. The method of  claim 4 , wherein the reactive material stack is a component of a phase change memory cell, and the reaction produces sufficient heat to cause alteration to a memory state of the phase change memory cell. 
     
     
       7. A method of forming a reactive material stack, the method comprising:
 forming a layer of a first reactive material over a substrate; 
 forming a layer of a second reactive material over the layer of the first reactive material; 
 forming a barrier layer over the layer of the second reactive material; and 
 repeating the forming of the layer of the first reactive material, the forming of the second reactive material, and the forming of the barrier layer to provide a desired thickness for the reactive material stack, wherein the barrier layer comprises a stack of, and from bottom to top, Al x O y /Ta/Ta x O y  or, Al x O y /Ta/Ta x O y /Ta/Ta x O y , wherein x is from 1 to 3 and y is from 1 to 5. 
 
     
     
       8. The method of  claim 7 , wherein the desired thickness is from 0.5 μm to 10 μm. 
     
     
       9. The method of  claim 7 , wherein the first reactive material and the second reactive material are selected from the group consisting of Ni/Al, Al/Pd, Cu/Pd, Nb/Si and Ti/Al. 
     
     
       10. The method of  claim 7 , further comprising reacting the first reactive material and the second reactive material, wherein the reaction causes intermixing of the first reactive material and the second reactive material to form an alloy, intermetallic or a composite of the first reactive material and the second reactive material. 
     
     
       11. The method of  claim 10 , wherein the reaction comprises an ignition caused by one of mechanical stress, an electrical spark, or a laser pulse. 
     
     
       12. The method of  claim 7 , wherein the reactive material stack is a component of a phase change memory cell, and the reaction produces sufficient heat to cause alteration to a memory state of the phase change memory cell.